1. Field of the Invention
This invention relates to pharmacologically active compounds useful in the treatment of allergic and inflammatory conditions, particularly allergic asthma and hay fever. Those compounds are classifiable in U.S. Classes 260/308D and 260/345.2 and in International Class C07d 7/34.
2. Description of the Prior Art
U.S. Pat. No. 3,882,148 (5/75; "Augstein") discloses a genus of compounds having the structure, ##STR1## in which: each of substituents R.sup.1 -R.sup.5 and R.sup.7 can be a hydrogen atom, a hydroxyl, alkoxyl, benzyloxyl, acyl, amino, acylamino, alkenyl, halogeno, or an alkyl group; X can be a hydrocarbon chain of from 2 to 10 carbon atoms optionally substituted by a hydroxyl group; and E can be a tetrazolyl or carboxyl group.
Because I contains structural features not germane to the present invention, it is convenient to simplify that formula to ##STR2## in which R can be a hydrogen atom, a halogeno, hydroxyl, or an alkyl group. While Augstein does not provide specific examples of Ia, that reference nevertheless provides generic disclosure of those compounds. The disclosure in Augstein, however, does not include compounds having structure I or Ia in which R is a cyano group.
Augstein discloses that compounds having structural formula I are useful in the treatment of disorders in which SRS-A (slow reacting substance of anaphylaxis) is a factor, such as asthma, hay fever, skin disorders and diseases of the respiratory system.
U.S. Pat. No. 3,899,513 (8/75; "Warren") describes compounds having the structure, ##STR3## in which: R.sup.1 can be a hydrogen atom, a nontoxic cation, or an alkyl group of 1 to 4 carbon atoms. Compounds III are useful as starting materials for those disclosed in this specification. Warren teaches that compounds III are useful in the treatment of allergic conditions.
Example 5 of this specification demonstrates that the claimed compounds have therapeutic indices superior those of compounds Ia and III.